1. Field of the Invention
The present invention relates to a technique for displaying video data.
2. Description of the Related Art
As a result of enhancements in the performance and reductions in the price of digital devices, high-definition video data can now be easily captured even with low cost digital cameras, mobile telephones and the like in generally widespread use. Also, as a result of increases in the capacity of storage installed in these devices, it is now possible for anyone to store enormous amounts of video data. And a situation has arisen where storages are now overflowing with these enormous amounts of stored video data.
Retrieving and browsing desired scenes or the like from enormous amounts of video data is difficult in such a situation. For this reason, retrieval techniques and metadata annotation techniques that use various types of video analysis have been proposed. However, even if such conventional techniques are utilized, retrieving a desired scene with only various types of meta-information added to the data is difficult, especially with multimedia data such as video data. This is because without actually checking multimedia data such as video data visually, it is ultimately impossible to judge whether that data (scene) is a desired scene or not. In other words, with the conventional methods of retrieving and browsing video data, excessive amounts of time and daunting operations were needed to retrieve and check desired scenes from enormous amounts of video data.
For example, in the case of browsing video data, typical methods involve browsing video data one at a time while reproducing or fast forwarding, or browsing important-looking video scenes, using chapter frames or index frames generated and displayed by extracting video frames from video data at an arbitrary frame interval as a cue. As a result, retrieving and browsing video data takes time.
In order to solve such problems, a technique for determining reproduction positions of video data using video analysis information rather than information added to video data (Japanese Patent Laid-Open No. 2004-120553), and a technique for generating a summary of video data (Japanese Patent Laid-Open No. 2006-345554) have been proposed.
In these conventional techniques, proposals are made to make it easier for a user to find an intended scene by using video analysis information, compared with the case where only additional information added to video data is used.
Meanwhile, a technique for freely accessing arbitrary scenes in video data (United States Patent Laid-Open No. 2008/0152299) has been proposed. The basic mechanism of this technique involves extracting the video of portions directly designated with a user interface (UI) in units of frames, and sequentially reproducing and displaying the extracted video according to the operation speed. Increases in the browsing speed of video frames in video data and improvements in operability are sought as a result of this mechanism.
However, with these conventional techniques, important scenes in video data may be overlooked. For example, there is a possibility that important scenes that the user would originally have desired will be dropped from a video data summary obtained using video analysis information, since important-looking scenes are extracted and displayed based totally on the video analysis information. If an important scene that the user desires is missing from a video data summary, the original video data must be checked once again.
Also, similar problems arise in the case of the video data display method for reading video frames from video data, and reproducing and displaying the video frames of arbitrary sections at a reproduction speed that depends on the operation speed. In other words, since the sampling interval of video frames to be reproduced and displayed is fixed, problems arise such as the video frames of important scenes getting dropped, or reproduction and display of the video frames of important scenes being jumpy, making it impossible to grasp the content.